1. Field of the Invention
The present invention relates to a method of producing a coating layer on a localized area of a component made of a superalloy, particularly a component intended for use in an aeronautical application such as an aircraft engine.
2. Summary of the Prior Art
It is known in numerous applications to require particular functional properties in localized areas of components, such as improved wear resistance or improved oxidation stability, depending on a variety of particular stresses or contacts. For this purpose, various processes have been proposed to achieve the joining of a coating layer element to a component. For example, FR-A-2317259 envisages melt deposition, using welding means, of a layer of a crack-resistant alloy on the tip of a blade, followed by a layer of hard and/or oxidation/corrosion-resistant alloy. However, melt coating processes are limited by the very low weldability of nickel or cobalt based superalloys, particularly in the cast state.
FR-A-2511908 describes a diffusion brazing joining method which enables an elementary part in the form of a pre-sintered blank obtained from a mixture of two powders to be added to a nickel or cobalt based superalloy component. However, depending on the particular surface properties sought in certain applications, it is not possible in certain cases to obtain a satisfactory self-brazable material from a homogeneous mixture of powders.
In FR-A-2691658, a coating layer element is obtained from the production of three successive layers by plasma flame spraying. However, this solution is applicable only when the joining surface is flat, and also requires that pressure should be applied to ensure metallurgical bonding. Furthermore, the thickness of the deposition is limited to 1 mm.